As with a rapid development of photography technology, the demand on thin, small, and light electronic products (e.g., digital cameras, digital camcorders, smart phones, and tablets) equipped with an image pickup device is higher and higher.
Collapsible zoom lens is a stretchable lens, which can be outstretched beyond the body of a camera, and the lens barrier is stretchable in zooming. In use, the lens groups of this type of lens have to be frequently stretched and need to be stretched out from the body. Therefore, the lens may malfunction due to collisions easily occurred. Also, in this type of lens, the distance is much longer in zooming, and thus the lens cannot satisfy the demand on thinness.
Optical zooming and focusing for an inner zoom lens or a periscope lens are accomplished inside the body. The lens does not need to be stretched out from the body. Therefore, the image pickup device can be small in size, the volume is reduced, and the demand on thin, small, and light products can be met. Also, the lens is protected without damage since the lens does not have to be stretched out from the body. In addition, the length of the lens barrier of the inner zoom lens is fixed, and thus the lens is sealed better than the collapsible zoom lens.
The present invention devotes to develop a thinner lens product and meanwhile satisfy the requirement of excellent imaging performance under the optical structure of an inner zoom lens.